Deep Sea Cabled Infrastructure Observatories Design Criteria and Philosophy for Shore-end Cable Stations

Science communities around the world are installing, or proposing to install, a new generation of cabled infrastructure that will provide standard communications and power interfaces in the deep ocean. An essential, though often overlooked, part of any cabled system is the shore station, from which the system is powered, and through which all data flows. Shore stations are often some distance from the host institution, and may be in remote locations where power is uncertain and communications limited. They will need to support unmanned operations to manage operating costs, without putting the data stream at risk. This paper will make the case, using examples from the outfitting of the NEPTUNE Canada shore station in Port Alberni, BC, that shore station infrastructure design needs careful attention for a cabled observatory to be successful. Given the life expectancy of the system, the rapid changes in technology and increases in power seen for many scientific and computing applications, as well as the expectation that the system will be expanded and connected to other observatories during its lifetime, the shore end infrastructure must be designed such that it can support a range of operational configurations with minimal impact to the operation of the existing systems. To accomplish this, careful consideration has to be given to the upgradability of the various shore station components, since budget constraints dictate that the ultimate design capacity of the facility cannot be installed initially. Given the risk of damage to the underwater plant in the event of major power surges, the electrical equipment must be designed to isolate the power feed to the shore station telecommunications system and underwater equipment from the local electricity grid. The operators and users of the observatory have, as their primary interest, the data received from the instruments connected to the sub-sea cable system. Operation and care of the shore-end facilities is a secondary co- ncern of the observatory users, so the shore station must be easy to operate and maintain. Extensive remote monitoring and automation of the shore station equipment is required to support unmanned operation.